Festive Fun on Treasure island

I said in my sidebar "About me" that I get to play games with my grown up kids occasionally and Christmas is generally the best time for this. We have 3 of the offspring, plus partners, for the festivities this year and they all seemed keen on my suggestion to put on a light hearted pirate treasure seeking "wargame". I was inspired by Charles Grant's "Trouble on Treasure Island" scenario in the